Ear & CNS Flashcards
Parts of Middle ear
- Tympanic cavity
- Auditory ossicles
Auditory (eustachina/pharyngotympanic) tube
Which nerve is in close proximity to the middle ear?
Facial Nerve- CN. 7
What is the function of the Eustachian Tube?
It is a canal that connects the middle ear to the nasopharynx, which consists of the upper throat and the back of the nasal cavity. It controls the pressure within the middle ear, making it equal with the air pressure outside the body.
What protects the ear from loud sounds?
Stadium m. (muscle of stapes)
Explain how sound is transmitted from the external ear to the middle ear
Vibration of sound on the tympanic membrane is transmitted through the middle ear to the cochlea via the ossicles
Part of the inner ear that contains perilymph
Bony Labyrinth
Part of the inner ear that contains endolymph
Membranous Labyrinth
3 auditory ossicles in the middle ear
- Malleus
- Incus
- Stapes
Part of the inner ear that contains utricle & saccule
Vestibule
What produces endolymph?
Stria vascular
Organ for hearing & equilibrium
Inner ear
“sound-collecting & conducting apparatus”
external ear & middle ear
List the Meninges & their location
- Dura mater (outermost layer)
- Arachnoid (attached to dura matter)
- Pia mater (inner most, adherent to brain & spinal cord. highly vascular)
What does white matter in the brain contain?
myelinated axons glial cells, blood vessels
What does gray matter contain in the brain?
neurons, glial cells, axons, & blood vessels
Oligodendrocytes are glial cells that do what?
provide support & production of myelin sheath to axons within the CNS
What are the functions of Microglia ?
function as macrophages (scavengers) in the central nervous system. Immunosurveillance, Immunoregulation, Reparative (phagocytic)
Gitter cells
they are microglial cells that are globular & swollen after having phagocytize debris from injured cells. They are weighed down with degenerating myelin.
Ectodermal Origin (sensitive to hypoxia, meaning they can’t survive without oxygen)
neurons
astrocytes
oligodendrocytes
Mesodermal origin (not as sensitive to hypoxia, so they can survive longer without oxygen)
Microglia
Vascular endothelium
Neuroglia/Glial Cells/Glia “Glue”
support cells within the brain & outnumber neurons 50:1
Some of these form myelin
List types of neuroglia
- Astrocytes
- oligodendrocytes
- Ependymal cells
- Microglia
Two Types of Astrocytes
Protoplasmic (gray matter)
Fibrillar (white matter)
Functions of Astrocytes
- transport of nutrients
- part of blood brain barrier
- antigen presentation
* very numerous*
What forms myelin?
Oligodendrocytes form Myelin in the CENTRAL NERVOUS SYTEM. Schwann cells make it int PERIPHERAL NERVOUS SYSTEM
What produces CSF?
choroid plexuses of the lateral, 3 & 4th ventricles of the brain
The fetal cerebellum& cerebellum of a new born has an additional _____
exterior cortical lamina
Are nerves & ganglia found inside the CNS?
No. They are found OUTSIDE the CNS
List the cells present in a nerve
Endothelial cells, fibroblasts, schwann cells
List the two types of Ganglia
- Sensory (craniospinal)
2. Autonomic
What is the myenteric plexus?
it is the major nerve supply to the GI tract & controls GI tract motility. It helps control peristaltic movement of the gastrointestinal tract circular. It is situated between the inner & outer longitudinal layers of the tunica muscular
